1. Field of the Invention
The invention is related to an apparatus for hanging an engine propulsion unit upon an aircraft cell, enabling the setting of an engine attachment through a small recess provided in the cell. The invention is further related to tooling and a process of installing the apparatus.
2. Description of the Prior Art
French Pat. No. 2,326,327 provides an example of an apparatus for hanging an engine propulsion unit. Suspension from the cell is carried out in part by a central bolt and by lateral control links. The bolt transmits transverse thrust forces to the cell and permits vertical movements between the engine propulsion unit and the cell, while the links ensure the suspension of the unit from the cell. The bolt further serves as a centering element for the unit during the setting phase of assembly. At the end cooperating with the engine unit, the hollow bolt holds an anchoring element which is free to slide along the axis of the bolt and is threaded inside of the bolt. Upon assembly, a hoisting bar is introduced into the bolt and is screwed at one end into the anchoring element. At the other end is attached a hoisting cable connected to a winch. When the control links are attached, the hoisting wire and the bar are disassembled, freeing the anchoring element and enabling transverse displacements of the group with respect to the cell.
With this apparatus, centering and suspension are obtained using different elements. Access to bolt necessitates an inspection door and an access hole adequately sized to enable passage of assembly tools and the hoisting cable. However, in military aircraft, the need to increase fuel reserves to the greatest extent possible requires the use of the least possible area within the cell.